Unknown problems with Nextcloud

BusyContacts can handle everything smoothly. Sadly not davdroid.
I thought well maybe 20 contacts is too much for davdroid so from nextdroid interface I've made new contact list and made ONE contact.
Still too much. Oh yes I've made the logs http://paste.fedoraproject.org/539627/48568702/
I tried to run the davdroid on owncloud 9.2 and on nextcloud 11 doesn't work. BusyCal and BusyContacts work easily and auto discover paths. This software needs help so find urls...but no contacts, no callendars no nothing and few dollars less in my pocket.

Ok, the topic of 1 contact was to show that issue is not with many contacts.
About refund. It's just annoying for paid app to behave like this.
After spending 2 nights digging myself the topic I see that whole dav syncro is some nightmare.
But well, let's try to solve it, maybe you guys have some ideas.

@kamil Unfortunately, information is not enough to make any helpful guesses. I don't even know what your actual problem is. If you want a refund, please send your Google Play transaction to play+davdroid@bitfire.at.

@rfc2822
That app looks like it's syncing.
It's able to create contact lists /calendars but it's not able to sync contacts/calendars. It's able able to discover paths..but the final sync doesn't works. I've checked in the contacts if there is davdroid's list of contacts and there is. Sadly empty. Android is miui, nextcloud is on vesta but I have just now modified whole nginx config to be identical to the one from nextcloud's website.